Essential Biology Concepts: Anatomy, Botany, and Metabolism
The Human Eye
The eye is the sense organ responsible for vision. It detects light and converts it into nerve impulses that are interpreted by the brain.
Structure and Functions
- Cornea: Transparent front part; refracts (bends) light.
- Sclera: Tough white outer layer; protects the eye.
- Choroid: Middle pigmented layer; nourishes the eye and prevents internal reflection.
- Iris: Colored part; controls the size of the pupil.
- Lens: Transparent, biconvex; focuses light on the retina (accommodation).
- Optic nerve:
Diffusion and Osmosis: Principles of Passive Transport
Understanding Diffusion
Diffusion is the net movement of particles from an area of high concentration to an area of low concentration.
Key Characteristics of Diffusion
- It happens in liquids and gases.
- Particles move randomly all the time.
- It is a passive process.
- It does not need energy from the cell.
Diffusion in Biological Cells
Cell membranes are partially permeable. This means:
- Small molecules can pass.
- Large molecules cannot pass easily.
Diffusion happens across the membrane when there is a concentration
Read MoreEnvironmental Science: Ecosystems, Pollution, and Resources
Ecosystem Definition and Functional Units
Definition: An ecosystem is a community of living organisms (plants, animals, and microorganisms) that interact with each other and with non-living components (air, water, soil, sunlight, and minerals) in a particular area. It is a basic functional unit of nature where energy flows and nutrients are recycled.
Core Components of an Ecosystem
1. Biotic Components (Living Components)
These are the living parts of an ecosystem:
- Producers: Green plants that make their
Mass and balance
BIO DIVERSITY Variation = differences btwn organisms; physical (size, colour, shape) or behavioural.~Interspecific = btwn species. Intraspecific = within same species.~Species = organisms that can interbreed + produce fertile offspring.~Biodiversity = variety of life; ↑ variation = ↑ biodiversity.~Adaptation = variation that improves survival/reproduction.• Structural = physical trait• Behavioural = action/behaviour~Natural Selection: helpful variation → survive/reproduce → trait passed
Read MoreHuman Respiratory and Urinary System Anatomy
The Respiratory System
The respiratory system is a group of organs and tissues that help us in breathing or respiration. This group of organs and tissues is known as the respiratory tract, which includes the passage of air from the nose to the alveoli in the lungs.
- Path: Air → O₂ (Oxygen)
- Breathing: This is generally a physical and mechanical process of taking air (O₂) into the body/lungs and expelling it (CO₂).
- Respiration: This is the complete biochemical process of exchanging gases (O₂/
Biochemistry: Metabolism, Enzymes, and DNA Replication
The Glycolysis Pathway
Glycolysis is a biochemical pathway in which one molecule of glucose (a 6-carbon compound) is converted into two molecules of pyruvic acid (a 3-carbon compound) through a series of enzyme-controlled reactions. It occurs in the cytoplasm of all living cells and does not require oxygen directly, making it an anaerobic process.
During glycolysis, energy is produced in the form of ATP and NADH. It consists of two phases:
- The energy investment phase
- The energy payoff phase
Glycolysis
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